1. Field of the Invention
The present invention is directed generally to the management of waste ink accumulated in an ink jet printer, and more particularly, to an apparatus and method for increasing the effective capacity for storing waste ink in a maintenance station without increasing the physical capacity of the waste ink collection reservoir.
2. Description of the Related Art
Maintenance operations are required by ink jet printers to keep the nozzles of the print cartridge operating properly. Typically, such maintenance operations include a combination of wiping the nozzle area of the print cartridge, firing the nozzles at prescribed intervals (spitting), and capping the cartridge during idle periods to prevent the jetted ink which remains on the nozzle plate from evaporating and drying on the nozzle plate, which in turn can clog one or more of the nozzles of the nozzle plate. Typically, the spitting operation occurs at a location in the maintenance station. Thus, the maintenance station includes some sort of reservoir for accumulating waste ink.
A variety of attempts have been made to handle and transfer waste ink in an ink jet system. One such attempt is directed to an apparatus having a pump mechanism for carrying waste ink from the pump to a carrying member. Waste ink is supplied to the pump by a series of ink-absorbing materials that, by capillary action, transfer the waste ink to the pump. During operation, a print head wiper slides in contact with a wipe-over portion of an ink-absorbing member carried by an ink-absorbing spring at a predetermined position on the chassis, whereby ink, water droplets, and contaminants adhering to the wiper are imparted to the ink-absorbing member. The ink or water droplets adhering to the ink-absorbing members transfer from one member to another by capillary action, and ultimately to the pump mechanism for carrying waste ink from the pump to a waste ink carrying member.
Early ink jet printers used dye-based inks, which were mostly volatile liquids, and the maintenance operations required little capacity for waste ink generated from the spitting operation due to evaporation of the volatile liquid component of the ink and the relatively small quantity of solids in the ink. More recent products, however, have incorporated pigment-based inks that have a larger percentage of solids in them. After the volatile components evaporate, a sludge of mostly solid material is left behind. This solid material builds up in or below the maintenance assembly, and over time, storage capacity must be provided for the solid buildup in order for the maintenance station of the printer to operate properly. To address this increase in capacity, one method would be to increase the size of the waste ink collection reservoir for collecting the waste ink. Such an increase in capacity for collecting waste ink, however, would result in increased size of the printer and/or increased cost relating to the increased capacity for the waste ink collection reservoir.
What is needed in the art is a printing system that includes a maintenance station that has the ability to effectively increase the amount of waste ink that can be collected without physically increasing the size of the waste ink collection reservoir.
The present invention provides a maintenance unit for use in an ink jet printer having a printer frame and having a waste ink accumulation region.
In one form of the invention, the maintenance unit includes a maintenance frame coupled to the printer frame; a maintenance sled moveably coupled to the maintenance frame; and a spreader mechanism slidably coupled to the maintenance frame. The spreader mechanism is driveably coupled to the maintenance sled. The spreader mechanism contacts waste ink to distribute the waste ink over the waste ink accumulation region as the maintenance sled moves relative to the maintenance frame.
As one aspect of the invention, the spreader mechanism is controllably moved horizontally with respect to the maintenance frame.
As another aspect of the invention, the spreader mechanism is controllably moved both horizontally and vertically with respect to the maintenance frame.
An advantage of the present invention is that the amount of waste ink that can be collected without physically increasing the size of the waste ink collection reservoir is increased.
Another advantage is that the service life of an ink jet printer into which the present invention is incorporated is increased.